2.2.3.6.2. positive feedback: keeps variable outside normal ranges and response does not turn off (accelerates to completion E.g childbirth and the release of oxytocin)

2.2.3.6.3. negative feedback keeps the conditions within the normal range which is needed for survival

3. complex: macroscopic level

3.1. tissues: cells formed together that perform a similar function

3.1.1. blood: a fluid connective tissue composed of plasma and other elements. includes erythrocytes, leukocytes and plasma

3.1.1.1. structure: biconcave in shape no organelles only room for hemoglobin

3.1.1.2. function: gas transportation which is done through hemoglobin

3.1.1.3. hemoglobin: binds with oxygen in lungs where oxygen levels are high and releases them into tissues where oxygen levels are low. binds with carbon dioxide in tissues that are high and transports them in the lungs where carbon dioxide levels are low and vie versa

3.1.2. blood role in homeostasis

3.1.2.1. distribution

3.1.2.1.1. O.M.H

3.1.2.1.2. oxygen and nutrient levels

3.1.2.1.3. metabolic waste

3.1.2.1.4. hormones

3.1.2.2. regulation

3.1.2.2.1. I.P.F

3.1.2.2.2. ISF and electrolyte levels

3.1.2.2.3. pH using chemical buffers

3.1.2.2.4. fluid volume and body temp

3.1.2.3. protection

3.1.2.3.1. infection control

3.1.2.3.2. preventing blood loss

3.2. organs: greater than 2 tissue types working together to performa a similar function

3.3. organ system: organs working together

3.3.1. support and movement: muscular system, skeletal, integumentary

3.3.2. control and regulation: endocrine, nervous system

3.3.3. fluids, transport and defense: cardiovascular and lymphatic system